MG-Cars.net

Welcome to our resource for MG Car Information.

Recommendations

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MGB Technical - hard brakes

i have a 74 b. Aprox two weeks ago i discovered the master brake cylinder was empty, there was no evidence of leaks arount the car. After refilling with brake fluid and bleeding the brakes everything appeared fine. However the other day when i applied the brakes the pedel felt rock hard, but when it was pumped it felt normal. This has happened a couple of times. does anyone have any idea what is cusing this problem and the solution.
rick

Hmmm, rock hard or not, something's rotten in the state of Denmark ... the brake system should not lose any fluid whatsoever, period. Something's surely leaking. May well be worth a careful check.
Ted

Sounds like a servo problem.
George B.

Where servo's fitted on 74' ?
Dom

Sorry : 'Were'
Dom

If you lost all of your fluid, you have a leak somewhere, it probably just didn't hit the ground. I'd guess a rear cylinder is dribbling, and the crud built up on your backing plate is acting like a sponge (and possibly, your brake shoes are soaking up their fair share). If your pedal gets normal when pumped, that's typical of a leak in the system - fluid gets out, air gets in.

An extremely hard pedal can mean something which should be moving is not. A slave cylinder may be seized or a return spring may not be doing its job. However, conquer the leak first.

Start at the wheels. Check for leaks, free movement of all parts and broken springs. On the rear cylinders, pull the rubber boot back a bit. Fluid should not dribble out.

Next, check the condition of your steel and rubber brake lines. Remember that rubber can look worse on the inside than outside. If the rubber has cracks or is damp, replace it.

If the master cylinder is leaking fluid, it'll be wet and/or there'll be a puddle near it. In an MG it'll be on your right pants leg. If it's holding pressure and not leaking, it's probably okay.

When you get to some actual repair, remember that new slave cylinders are remarkably cheap. Replace them if they're at all questionable. Springs and shoes aren't very expensive either by modern standards.

In any case, you owe it to your family, your car and anyone you may collide with to take that brake system apart and give it an inspection ASAP.

Best wishes,

Matt K.
Matt Kulka

BTW even if the brake lines don't look too bad, they could be acting as a one way valve. If they are over four years old, I would replace them. I just replaced mine with the SS/teflon version and my brakes have never been better.
Luis

Luis

Where did you get the SS/teflon brake hoses? VB (catalog I have here on my desk at work) lists SS but no mention of teflon inner tubing.

Thanks

Larry
Lawrence Hallanger

Got them through Moss. But check with Proper MG. I just found out they had the same ones on sale.
Luis

BTW, the box also said they had a lifetime warrenty. Who's lifetime is anyone's guess.
Luis

Luis

Doesn't that mean the lifetime of the brake lines?

Thanks for the info.

Larry
Lawrence Hallanger

Yeah, maybe. The lifetime of the brakelines, the car, you, me, the president of the company that sold it, the flea next to the car when you installed it. Whatever.

Its usually open to the interpretation of lawyers.
Luis

This thread was discussed on 25/09/2002

MG MGB Technical index

This thread is from the archive. The Live MG MGB Technical BBS is active now.